Common types of air pollution led to changes in teenagers’ blood pressure, study finds

Scientists know that air pollution can make it difficult to breathe and ultimately cause serious health problems like cancer, but a new study shows it could also have a negative impact on teens’ blood pressure.

Exposure to higher nitrogen dioxide levels was associated with lower blood pressure in teenagers, according to the study published Wednesday in the journal PLOS One. Exposure to particulate matter 2.5, also known as particle pollution, was associated with higher blood pressure.

The effects are “significant,” the researchers say.

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Other studies have found an association between blood pressure changes and pollution, but much of this work focuses on adults. Some research has also found negative associations with pollution and younger children, but little has focused on teenagers.

In general, low blood pressure can cause immediate problems such as confusion, tiredness, blurred vision, and dizziness. High blood pressure in adolescence can lead to lifelong health problems, including a higher risk of stroke or heart attack. It is a leading risk factor for premature death worldwide.

The study did not look at whether the teens had any symptoms or health effects from the change in blood pressure.

The scientists found this link between pollution and blood pressure in data from the Determinants Of Adolescent Social Well-Being And Health study, which tracks the health over time of a large and ethnically diverse group of children in London.

The researchers took data from more than 3,200 teenagers and compared their records to their exposure to pollution based on the annual pollution levels in their area.

Nitrogen dioxide pollution is most commonly associated with traffic-related combustion by-products. Nitrogen can help plants grow, but it can affect a person’s ability to breathe and damage human respiratory systems. In this study it was assumed that the nitrogen mainly comes from diesel traffic.

The particle load in the study is so tiny – 1/20 the width of a human hair – that it can pass through the body’s normal defenses. Instead of being performed on the exhale, it can get stuck in the lungs or enter the bloodstream. The particles cause irritation and inflammation and can lead to a whole range of health problems.

Particle pollution can come from wildfires, wood stoves, power plants, and coal fires. It can also come from traffic and construction sites.

In this study, the association between exposure to pollution and changes in blood pressure was stronger in girls than in boys. The researchers can’t determine why there’s a gender difference, but they found that 30 percent of the female participants in the group got the least amount of exercise and noted that this may have an impact on blood pressure.

“It is therefore imperative that air pollution levels in London are improved in order to maximize the health benefits of physical activity among young people,” the study states.

Although the study also fails to determine why teenage blood pressure changes with exposure to air pollution, others have found that exposure to air pollution can affect the central nervous system, causing inflammation and damage to the body’s cells.

Additionally, exposure to particulate pollution can disrupt a person’s circadian rhythm, which could affect blood pressure. Exposure to particulate pollution can also decrease the kidneys’ ability to excrete sodium during the day, leading to higher nighttime blood pressure, the study said.

Regarding nitrogen dioxide pollution, the researchers previously conducted a crossover study examining the blood pressure of 12 healthy adolescent participants exposed to nitrogen oxides from a domestic gas stove with lit burners. Their blood pressure dropped compared to participants who were only exposed to room air.

In the new study, the links between pollution and blood pressure were consistent. Height, socioeconomic status, and ethnicity did not change the results.

However, it only looks at teenagers in London, and only 8 percent of them were people of color. The study found that these children were exposed to higher levels of pollution than Caucasian children.

Pollution levels in London are also well above what World Health Organization guidelines consider safe for humans. However, the same is true for most areas of the world. In 2019, 99 percent of the world’s population lived in places that did not meet WHO recommended air quality levels.

Previous work has shown that pollution can damage young people’s health and put them at higher risk of chronic diseases, such as heart problems, later in life. Studies in adults found that exposure to air pollution can affect blood pressure even within hours of exposure.

According to another study, pollution caused 1 in 6 deaths worldwide in 2019 alone.

Some experts suggest reducing the risk of pollution-related health problems among teenagers by investing in portable air purifiers with HEPA filters, which are highly effective in reducing indoor air pollution. The filters can’t eliminate the entire problem, however, and experts say community-wide public policy solutions are needed.

Johns Hopkins Medicine Assistant Professor of Pulmonary and Critical Care Medicine, Dr. Panagis Galiatsatos said research like this is important to develop a hypothesis about what these pollutants are doing to humans. Galiatsatos, a volunteer medical spokesman for the American Lung Association, was not involved with the new study.

“A lot of this air pollution tends to accumulate in economically deprived neighborhoods, so that’s one of the main reasons we always want to keep a close eye on this, as certain population groups are disproportionately affected more than others,” he said.

Blood pressure is an important marker of health as it is a surrogate for understanding the more complex processes that may be going on in the body.

“My big takeaway is that these toxins clearly appear to have a physiological impact on the cardiovascular system and any manipulation should be viewed in the context of concern,” Galiatsatos said.

The co-author of the study, Dr. Seeromanie Harding, professor of social epidemiology at King’s College London, hopes it will lead to more research on the topic.

“With over a million under-18s living in (London) areas where air pollution levels are above recommended health standards, there is an urgent need for more of these studies to provide an in-depth understanding of the threats and opportunities for young people gain development,” she said.